VCDX Admin Exam Notes – Section 1.3

Ugh. My brain hurts. I’ve spent the past few hours reviewing scripted ESX installations and working on a PowerShell script for a customer that will reorder vmnics after a scripted installation is complete (because I can’t find any other way to force their order during the install). It’s been a few months since I’ve done a scripted installation, so I definitely needed a refresher. Plus, according to the VMware Enterprise Administration Exam Blueprint v3.5, section 8.1 is all about automating ESX deployments. The good news is that section 8.1 is the last section of the blueprint, so I believe I’m almost done preparing for the VCDX Admin Exam, which I’m scheduled to take in a few days.

Anyway, going back to the beginning of the Blueprint, and continuing from where I left off, here is the next section of my study notes.

All storage related events will be recorded in the /var/log/vmkernel log file. Most of the messages in this log file are fairly cryptic and can be difficult to interpret. Furthermore, this log file contains all messages from the vmkernel, not just storage related messages, so you’ll have to filter through it. An easy way to do this is simply to search for SCSI. For example, the command cat /var/log/vmkernel | grep SCSI on one of my servers produces the following output (only showing the last 10 lines) …

If you look closely, I clearly had some issues with my iSCSI appliance a few hours ago. I decided make some configuration changes to the switch and then, all of a sudden, the ESX server lost connectivity to its storage. Weird! 🙂

Anyway, what does all this mean? There’s an really good VMworld Europe 2008 presentation (which you can get from www.vmworld.com) titled VI3 Advanced Log Analysis, which goes into detail about how to interpret VMware log files. From that presentation, I found this diagram which describes the components of a message in the vmkernel log file.

Failover events I don’t have redundant paths in my lab to simulate this. So, again from the VMworld presentation, VI3 Advanced Log Analysis, here is a screen shot from the slide that covers this topic.

There will obviously be a lot of different types of error and event messages in /var/log/vmkernel. And I’m certainly not going to try and list every possible combination here. I highly suggest you download the VMworld preso because it does a great job of explaining how to further decipher the log files (like defining SCSI error codes).

Well, that’s about it for this section. Back to PowerShell scripting for another hour or so.